Reversible Room-Temperature Ionic Liquids

ABSTRACT

One aspect of the present invention relates to salts that are room-temperature ionic liquids (RTILs), methods of making them, and methods of using them in connection with temporary or permanent gas sequestration. Another aspect of the present invention relates to a class of solvents which can be transformed into RTILs by exposure to a gas, and methods of using them in connection with temporary or permanent gas sequestration.

RELATED APPLICATIONS

This application claims the benefit of priority to U.S. ProvisionalPatent Application Ser. No. 60/898,116, filed Jan. 29, 2007; thecontents of which is hereby incorporated by reference.

GOVERNMENT SUPPORT

This invention was made with support provided by the National ScienceFoundation (Grant Nos. CHE-0350538 and CHB-0714317); therefore, thegovernment has certain rights in the invention.

BACKGROUND OF THE INVENTION

Ionic liquids are liquids composed of ions that are fluid around orbelow 100° C. (Rogers, R. D.; Seddon, K. R. Science 2003, 302, 792-793).Ionic liquids exhibit negligible vapor pressure, which makes themsuitable replacements for conventional solvents. Conventional solventslike dichloromethane, acetone, benzene, and methanol are volatileorganic compounds which contaminate soil and groundwater, pollute indoorair, and increase the level of greenhouse gases. Increasing regulatorypressure to limit the use of volatile organic compounds has sparkedresearch into designing ionic liquids that could function asenvironmentally friendly replacement solvents.

By virtue of their high polarity and charge density, ionic liquids haveunique solvating properties, and are being used in a variety ofapplications. In addition to applications include in organic synthesisas a green solvent, ionic liquid are used in novel materials science(liquid crystals, gels, rubbers); electrochemistry, for example, in fuelcells, electrodeposition processes and other electrochemicalapplications; in applications where water-based chemistry can beproblematic (for example, applications involving proton transfer ornucleophilicity); or in applications where certain coordinationchemistry could have a damaging effect on the substrates involved.

Some simple physical properties of the ionic liquids that make theminteresting as potential solvents for synthesis are the following: (1)They are good solvents for a wide range of both inorganic and organicmaterials, and unusual combinations of reagents can be brought into thesame phase; (2) They are often composed of poorly coordinating ions, sothey have the potential to be highly polar yet noncoordinating solvents;(3) They are immiscible with a number of organic solvents and provide anonaqueous, polar alternative for two-phase systems; and (4) Ionicliquids are nonvolatile, hence they may be used in high-vacuum systemsand eliminate many containment problems (Welton, T. Chem. Rev., 1999,99, 2071-2083).

A broad range of ionic liquids have been investigated in the past. Themost commonly studied systems contain ammonium, phosphonium, pyridinium,or imidazolium cations, with varying heteroatom functionality. Commonanions that yield useful ILs include hexafluorophosphate, [PF₆]⁻;tetrafluoroborate, [BF₄]⁻; bis(trifyl)imide, [NTf₂]⁻; and chloride, Cl⁻.Anions can control the solvent's reactivity with water, coordinatingability, and hydrophobicity. Accordingly, ionic liquids are relativelyadvanced, technological solvents that can be designed to fit particularapplications (Wasserscheid, P.; Welton, T. Ionic Liquids in Synthesis,VCH-Wiley: Weinheim, 2002; Rogers, R. D.; Seddon, K. R., Eds. IonicLiquids: Industrial Applications for Green Chemistry, ACS SymposiumSeries 818, American Chemical Society: Washington, 2002).

Interest in room-temperature ionic liquids (RTILs) has increasedenormously during the last decade because, among other applications,they may be used to replace less environmentally friendly (‘green’)solvents. Invariably, these ionic liquids are either organic salts ormixtures consisting of at least one organic component. The most commonsalts in use are those with alkylammonium, alkylphosphonium,N-alkylpyridinium, and N,N′-dialkylimidazolium cations.

A major drawback of many ionic liquids is their air and moisturestability. Many ionic liquids are hygroscopic; if used in open vessels,hydration will almost certainly occur. The degree to which this is aproblem will depend on the use to which the ionic liquid is being putand what solutes are being used. For example, the smallest amount ofwater can deactivate a highly reactive solute used as a catalyst(Chauvin, Y. et al. Angew. Chem., Int. Ed. Engl. 1995, 34, 2698-2700).

Similarly, supercritical carbon dioxide has also been employed as agreen solvent although it requires specialized equipment and reactionvessels. Carbon dioxide also shows solubility in many ionic liquids.Although it is known that amidines and alcohols react very rapidly withCO₂ to form amidinium carbonate salts, some of which are liquids at roomtemperature, they are stable only under scrupulously dry conditions(Hori, Y. et al., Chemistry Express 1986, 1, 224-227). Jessop hasdemonstrated that the fraction of the amidinium carbonate made bybubbling CO₂ through a carefully dried 1/1 mixture of1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1-hexanol can be returnedto its original state by bubbling through N₂ or Ar gas (Jessop, P. G. etal., Nature, 2005, 436, 1102). However, the uptake of CO₂ in DBU/alcoholsystems may not be quantitative at 1 atm pressure (Hori, Y. et al.,Chemistry Express 1986, 1, 173-176). Also, bubbling CO₂ through a dilutesolution of an N′-alkyl-N,N-dimethylacetamidine in water yields anacyclic amidinium bicarbonate, a reversible surfactant (Liu, Y. et al.,Science 2006, 313, 958-960).

It is desirable to provide solvent systems whose electrostaticproperties can be changed reversibly from relatively low polarity tovery high polarity by the addition of different gases. Transparentsystems open opportunities for interesting spectroscopic investigations.It is further desirable to develop systems which employ inexpensiveprecursor amidines and amines, some of which may exhibit liquidcrystallinity.

SUMMARY OF THE INVENTION

One aspect of the present invention relates to a class of solvents whichcan be cycled between a room-temperature ionic liquid (RTIL) state and anon-ionic solvent mixture by exposing the liquids sequentially to afirst gas and a second gas. In certain embodiments, the first gas iscarbon dioxide. In certain embodiments, the first gas is carbondisulfide. In certain embodiments, the first gas is nitric oxide. Incertain embodiments, the first gas is SO₂. In certain embodiments, thesecond gas is an inert gas. In certain embodiments, the inert gas isnitrogen (i.e., dinitrogen).

In certain embodiments, the RTILs of the present invention are derivedfrom the addition of carbon dioxide to a mixture of an aliphatic amidineand an amino acid alcohol. In certain embodiments, the RTILs of thepresent invention are derived from the addition of carbon dioxide to amixture of an aliphatic amidine and an amino acid ester. In certainembodiments, the RTILs of the present invention are derived from theaddition of carbon disulfide to a mixture of an aliphatic amidine and anamino acid alcohol. In certain embodiments, the RTILs of the presentinvention are derived from the addition of carbon disulfide to a mixtureof an aliphatic amidine and an amino acid ester. In certain embodiments,the aliphatic amidine is optically active. In certain embodiments, theamino acid alcohol is optically active. In certain embodiments, theamino acid ester is optically active. In certain embodiments, the RTILsof the present invention are optically active.

Another aspect of the present invention relates to a class ofroom-temperature ionic liquids (RTILs) which are derived from a moleculeor ion represented by

and a mixture of an amidine and an amine. Non-limiting examples of themolecule or ion include: SO₂, NO₂, NO₂ ⁻, N₃ ⁻, SCN⁻, OCN⁻, R—N₃, R—NCO,R—NCS, and R—OCN. These RTILs may be used in any of the methodsdescribed herein.

In certain embodiments, the RTILs of the present invention are easilyreversible amidinium carbamates derived from the addition of carbondioxide to a mixture of an aliphatic amidine and an aliphatic primaryamine. Remarkably, the ionic liquids of the present invention may bereconverted to low polarity solvents easily and reversibly by reducingthe pressure, heating, or bubbling an inert gas through the liquids. Incertain embodiments, the inert gas is molecular nitrogen (N₂). Theuseful temperature range may be increased by increasing the pressure ofcarbon dioxide. Thus, a second liquid component can be expelled ordissolved within the ionic liquid as it is reversed.

In certain embodiments, reversible, optically-active RTILs can be madeeasily from acyclic amidines and chiral amines. Accordingly, the ionicliquid systems of the invention may be useful in the pharmaceuticalindustry and other synthetically-related industries. In certainembodiments, these systems may be useful to effect chiral syntheses orseparations.

Another aspect of the invention is that these systems obviate thenecessity of employing specialized equipment, including maintainingabsolutely dry atmospheres, and offer the distinct advantage of creatingenvironments which can be made either to dissolve or phase separatesolutes and added liquid components depending on their polarity.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 depicts a class of solvents which can be cycled between a RTILstate and a non-ionic solvent mixture by exposing the liquidssequentially to CO₂ and N₂.

FIG. 2 depicts phases of neat 1/1 (mol/mol) amidine/amine mixturesbefore (B) and after (A) CO₂ bubbling. l, s, m, and g indicate(respectively) liquid, solid, liquid-solid mixture, and a glassytransparent material which crystallized partially over a period ofweeks.

FIG. 3 depicts plots of mole % CO₂ uptake by E+5 (), C+2 (Δ), E+6 (▴),and 5 (◯) as a function of time.

FIG. 4 depicts (i) Normalized UV-vis absorption spectra of thepolarity-sensitive dye, DAPNE(1-(p-Dimethylaminophenyl)-2-nitroethylene), in (from left to right)decane, E+5, THF, acetone, E5−C, and DMSO and (ii) UV-vis spectra of E+5(neat, solid line) and E5-C (neat, dashed line) in a 1 mm pathlengthcuvette.

FIG. 5 depicts ¹H-NMR spectra of 175 mM (a) C8/hexylamine and (b)C8/hexylamine+CO₂ in CDCl₃.

FIG. 6 depicts the chemical shifts of protons (a) and ¹³C(N═C—N(CH₃)₂)(b) in a 175 mM E+5 in CDCl₃ solution upon alternation between CO₂ andN₂ bubbling. For (a): N═C(CH ₃)—N (, 1.85-2.1 ppm), N═C—N(CH ₃)₂ (▴,2.85-3.15 ppm), and —CH ₂N═C—N (▪, 3.15-3.35 ppm)

FIG. 7 depicts the chemical shifts of CH ₂N═C—N (, ◯), (N═C—N(CH ₃)₂)(▴, Δ), and (N═C(CH ₃)—N) (▪, □) protons of different concentrations ofE+5 (opened symbols) and E5-C (closed symbols) in CDCl₃.

FIG. 8 depicts vertically offset IR spectra of (a) E+5 (neat) and (b)E5-C (neat). Samples were sandwiched between NaCl plates.

FIG. 9 depicts TGA curves for samples of neat (a) E+5 and (b) E5-Cheated from room temperature. Curve (c) is curve (a) minus curve (b).

FIG. 10 depicts phases of amidine/amino alcohol mixtures before andafter CO₂ bubbling. l, s, m, and g indicate (respectively) liquid,solid, liquid-solid mixture, and a glassy transparent material.

FIG. 11 depicts phases of amidine/amino acid methyl ester mixturesbefore and after CO₂ bubbling. l and s indicate (respectively) liquidand solid.

FIG. 12 depicts phases of amidine/amino acid octyl ester andamidine/amino acid octadecyl ester mixtures before and after CO₂bubbling. l, s, m, g, and l^(a) indicate (respectively) liquid, solid,liquid-solid mixture, glassy transparent material, and a liquid at roomtemperature which solidified in a refrigerator.

FIG. 13 depicts phases of amidine/amine mixtures before and after CS₂bubbling. l and s indicate (respectively) liquid and solid.

FIG. 14 depicts the optical rotation of chiral solvents which can be orhave been cycled between a RTIL state and a non-ionic solvent mixturebefore and after CO₂ bubbling.

FIG. 15 depicts selected examples of amidines, amino alcohols, and therelated RTILs according to the present invention, and a scheme for theassociated chemical equilibrium with carbon dioxide as the dissolvedgas.

FIG. 16 depicts measured viscosities for various RTILs of the presentinvention derived from an amidine, amino alcohol, and carbon dioxide.The acronyms used are as defined in FIG. 15.

FIG. 17 depicts TGA curves for C6/leucinol before (a) and after (b) CO₂exposure. Both were heated from room temperature. Curve (c) is curve (a)minus curve (b).

FIG. 18 depicts TGA curves for C8/ProOH (blue curve), C8/IleOH (greencurve), C8/LeuOH (red curve) and C8/ValOH (grey curve) after CO₂exposure, heated from room temperature.

FIG. 19 tabulates the time dependence of carbon dioxide uptake at roomtemperature by various mixtures (1:1 on a molar basis) of amino alcoholsand amidines according to the present invention (presented are averagevalues and data for individual samples).

FIG. 20 tabulates the phase appearances of various amino alcohol L/Acombinations at room temperature and −20° C. before and after bubblingCO₂ through the mixtures.

DETAILED DESCRIPTION OF THE INVENTION

One aspect of the present invention relates to a class of solvents whichcan be cycled between a room-temperature ionic liquid (RTIL) state and anon-ionic solvent mixture by exposing the liquids sequentially to afirst gas and a second gas. In certain embodiments, the first gas iscarbon dioxide. In certain embodiments, the first gas is carbondisulfide. In certain embodiments, the first gas is nitric oxide. Incertain embodiments, the first gas is SO₂. In certain embodiments, thesecond gas is an inert gas. In certain embodiments, the inert gas ismolecular nitrogen.

In certain embodiments, the RTILs of the present invention are derivedfrom the addition of carbon dioxide to a mixture of an aliphatic amidineand an amino acid alcohol. In certain embodiments, the RTILs of thepresent invention are derived from the addition of carbon dioxide to amixture of an aliphatic amidine and an amino acid ester. In certainembodiments, the RTILs of the present invention are derived from theaddition of carbon disulfide to a mixture of an aliphatic amidine and anamino acid alcohol. In certain embodiments, the RTILs of the presentinvention are derived from the addition of carbon disulfide to a mixtureof an aliphatic amidine and an amino acid ester.

In certain embodiments, the aliphatic amidine is optically active. Incertain embodiments, the amino acid alcohol is optically active. Incertain embodiments, the amino acid ester is optically active. Incertain embodiments, the RTILs of the present invention are opticallyactive.

In certain embodiments, the RTILs of the present invention are easilyreversible amidinium carbamates derived from the addition of carbondioxide to a mixture of an aliphatic amidine and an aliphatic primaryamine. Remarkably, the ionic liquids of the present invention may bereconverted to low polarity solvents easily and reversibly by reducingthe pressure, heating, or bubbling an inert gas through the liquids.

In certain embodiments, the RTILs of the present invention are derivedfrom the addition of carbon dioxide to a mixture of an aliphatic amidineand an amino alcohol. In certain embodiments, the RTILs of the presentinvention are derived from the addition of carbon dioxide to a mixtureof an aliphatic amidine and an amino acid alcohol. In certainembodiments, the RTILs of the present invention are derived from theaddition of carbon dioxide to a mixture of an aliphatic amidine and anamino acid ester. In certain embodiments, the RTILs of the presentinvention are derived from the addition of carbon dioxide to a mixtureof an aliphatic amidine and a chiral amino alcohol. In certainembodiments, the RTILs of the present invention are derived from theaddition of carbon dioxide to a mixture of an aliphatic amidine and achiral amino acid alcohol. In certain embodiments, the RTILs of thepresent invention are derived from the addition of carbon dioxide to amixture of an aliphatic amidine and a chiral amino acid ester. Incertain embodiments, the RTILs of the present invention are derived fromthe addition of carbon disulfide to a mixture of an aliphatic amidineand an amino alcohol. In certain embodiments, the RTILs of the presentinvention are derived from the addition of carbon disulfide to a mixtureof an aliphatic amidine and an amino acid alcohol. In certainembodiments, the RTILs of the present invention are derived from theaddition of carbon disulfide to a mixture of an aliphatic amidine and anamino acid ester. In certain embodiments, the RTILs of the presentinvention are optically active.

Another aspect of the present invention relates to a class ofroom-temperature ionic liquids (RTILs) which are derived from a moleculeor ion represented by

and a mixture of an amidine and an amine. Non-limiting examples of themolecule or ion include: SO₂, NO₂, NO₂ ⁻, N₃ ⁻, SCN⁻, OCN⁻, R—N₃, R—NCO,R—NCS, and R—OCN. These RTILs may be used in any of the methodsdescribed herein.

Although it is known that amidines and alcohols react very rapidly withCO₂ to form amidinium carbonate salts, some of which are liquids at roomtemperature, they are stable only under scrupulously dry conditions(Hori, Y. et al., Chemistry Express 1986, 1, 224-227). Jessop hasdemonstrated that the fraction of the amidinium carbonate made bybubbling CO₂ through a carefully dried 1/1 mixture of1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1-hexanol can be returnedto its original state by bubbling through N₂ or Ar gas (Jessop, P. G. etal., Nature, 2005, 436, 1102). However, the uptake of CO₂ in DBU/alcoholsystems may not be quantitative at 1 atm pressure (Hori, Y. et al.,Chemistry Express 1986, 1, 173-176). Also, bubbling CO₂ through a dilutesolution of an N′-alkyl-N,N-dimethylacetamidine in water yields anacyclic amidinium bicarbonate, a reversible surfactant (Liu, Y. et al.,Science 2006, 313, 958-960).

In certain embodiments where the first gas is carbon dioxide and thesecond gas is molecular nitrogen, remarkably, the amidine/aminecombinations can be interconverted repeatedly at room temperaturebetween their RTIL (Ln−C) and non-ionic liquid forms (L+n) by thetreatments shown in FIG. 1.

FIG. 2 depicts phases of neat 1/1 (mol/mol) amidine/amine mixturesbefore (B) and after (A) CO₂ bubbling. Diamines (e.g., 7 and 8) aremixed with 2 molar equivalents of amidines. Amidine/8 mixtures areheated gently to dissolve 8, and then CO₂ is bubbled through the warmsolutions. When DBU is the amidine, it is dried as described in theliterature and distilled (see Jessop, P. G.; Heldebrant, D. J.; Li, X;Eckert, C. A.; Liotta, C. L. Nature 2005, 436, 1102).

As shown in FIG. 2, in certain embodiments the phase remains liquidafter CO₂ bubbling. In other embodiments, a solid, liquid-solid mixture,or a glassy transparent material which crystallizes partially over aperiod of weeks obtains. Remarkably, 23 can be interconverted repeatedlyat room temperature between their RTIL (Ln−C) and non-ionic liquid forms(L+n) by the treatments shown in Scheme 1.

Primary amines react more readily with CO₂ than secondary (or tertiary)amines. In certain embodiments, the RTILs are more viscous than the L+nmixtures from which they are made. Qualitatively, the RTILs with 1 and 2are less viscous than the other Ln−C RTILs made from the same amidine.Evidence for the presence of amidinium carbamates comes from thermalgravimetric analyses (TGA) of the weight loss of CO₂ upon heating, fromfollowing the quantitative uptake of CO₂ by the L+n mixtures as afunction of time, and from comparisons of IR spectra of theamidine/amine mixtures before and after addition of CO₂. In certainembodiments, the uptake of CO₂ by neat amidine/amine solutions(including those with DBU as the amidine) is quantitative withinexperimental error when the resulting amidinium carbamate is a liquid atroom temperature (as opposed to neat DBU/alkanol toluene solutions).

In certain embodiments, in the absence of CO₂ the amidine/aminecombinations yield liquids at room temperature. In an embodiment with1,6-dimethylaminohexane (8), yielded a room temperature liquid solutionis made by heating it gently in the presence of an amidine partner. Incertain embodiments, the combinations employing ‘dried’ DBU remainliquids after addition of CO₂ except those with 8 or the bulkiest amine,t-butylamine (3).

The sensitivity of the systems to moisture depends on the nature of theprimary amine. When commercial DBU is used as received, only n-butylamine (1) and 1,2-diaminoethylene (7) yield RTILs upon addition of CO₂.Some RTILs employing even “dried” DBU (DBU1-C, DBU2-C, DBU5-C, andDBU6-C) become cloudy after standing for one day, indicating theaggregation of amidinium bicarbonates from residual water. However, whenCO₂ is bubbled through C+1 containing 3 wt % of added water, a liquidphase obtains and persists for long periods. Quite remarkably, thealiphatic amidine/amine systems can be easily adapted for manyapplications without maintaining scrupulously dry conditions.

In certain embodiments, longer chain lengths may discourage RTILformation. A comparison of the results from the acyclic amidines withthe isomeric butyl amines (1-3) provides additional insights into thedependence of the phase formed upon CO₂ bubbling and the molecularstructures of the constituent molecules. The unbranched n-butyl andsec-butyl amines yield ionic liquids with all of the acyclic amidinesstudied; however, t-butyl amine produces only solids. In otherembodiments, the acyclic amidines with the shortest n-alkyl chainlengths yield RTILs with cyclohexyl amine (4) and n-octyl amine (6).

Another aspect of the present invention is the quantitative uptake ofCO₂. The time dependence of the uptake of CO₂ by stirred mixtures ofC+2, E+5, and E+6, as well as by neat 5, can be followed using a gasburette filled with one atmosphere pressure of CO₂. In certainembodiments, about one-half an equivalent of CO₂ (47%) is taken up byneat 5; the formation of hexylammonium N-hexylcarbamate is virtuallyquantitative. Although the time profiles for uptake of the CO₂ gas mustdepend to some extent on the rate of stirring and the liquid-gas surfacearea, the data shows that the two mixtures which form RTILs (C+2 andE+5) behave very differently from the mixture which leads to a solid,E+6. In certain embodiments, uptake of CO₂ by C+2 and E+5 is rapidinitially and then continues very slowly, reaching a plateau value afterca. 30 min. The eventual uptake exceeds the theoretical amount by ca. 4and 10%, respectively. The solubility of CO₂ gas in many ILs is known tobe very high. Both the excess amount and the time profile for its uptakeindicate that the rapid (ca. 100%) part is due to formation of the RTIL;thereafter, more CO₂ dissolves in the ionic phase. In other embodimentsthe rate of uptake by E+6, leading to E6−C, is initially as rapid aswith the other amidine/amine samples, but slows after a short period oftime and reaches an eventual plateau corresponding to only ca. 73% ofthe theoretical value because solidification of E6−C traps the remainingliquid of E+6 and isolates it from contact with CO₂.

Another aspect of the present invention is the ability of these systemsto dissolve reversibly dissolve less polar materials into the L+n andseparate them from Ln−C as it is formed. For example, after bubbling CO₂through a transparent solution of E+5 and n-decane for <1 min, thesolution becomes opaque, but remains liquid. After additional bubblingfor 30 min and then standing for 60 min or centrifuging for a shortperiod, the sample separates into two liquid phases. In fact, phaseseparation can be achieved after as little as 1 min of CO₂ bubblingfollowed by standing. In other embodiments, cycling between one and twoliquid phases can be repeated 3 times by bubbling CO₂ and N₂sequentially to demonstrate the reversibility of the process.Remarkably, several interesting applications can be envisioned forsolvent systems whose electrostatic properties can be changed reversiblyfrom relatively low polarity to very high polarity by the addition ofdifferent gases. Additionally, the virtual transparency of both the L+nand Ln−C above ca. 350 nm and very low absorption at 300-350 nm opensopportunities for interesting spectroscopic investigations. The low costof and easy access to the precursor amidines and amines add to theattractive features of these systems.

DEFINITIONS

The term “heteroatom” is art-recognized and refers to an atom of anyelement other than carbon or hydrogen. Illustrative heteroatoms includeboron, nitrogen, oxygen, phosphorus, sulfur and selenium.

The term “alkyl” is art-recognized, and includes saturated aliphaticgroups, including straight-chain alkyl groups, branched-chain alkylgroups, cycloalkyl (alicyclic) groups, alkyl substituted cycloalkylgroups, and cycloalkyl substituted alkyl groups. In certain embodiments,a straight chain or branched chain alkyl has about 30 or fewer carbonatoms in its backbone (e.g., C₁-C₃₀ for straight chain, C₃-C₃₀ forbranched chain), and alternatively, about 20 or fewer. Likewise,cycloalkyls have from about 3 to about 10 carbon atoms in their ringstructure, and alternatively about 5, 6 or 7 carbons in the ringstructure.

The terms “heterocyclyl”, “heteroaryl”, or “heterocyclic group” areart-recognized and refer to 3- to about 10-membered ring structures,alternatively 3- to about 7-membered rings, whose ring structuresinclude one to four heteroatoms. Heterocycles may also be polycycles.Heterocyclyl groups include, for example, thiophene, thianthrene, furan,pyran, isobenzofuran, chromene, xanthene, phenoxanthene, pyrrole,imidazole, pyrazole, isothiazole, isoxazole, pyridine, pyrazine,pyrimidine, pyridazine, indolizine, isoindole, indole, indazole, purine,quinolizine, isoquinoline, quinoline, phthalazine, naphthyridine,quinoxaline, quinazoline, cinnoline, pteridine, carbazole, carboline,phenanthridine, acridine, pyrimidine, phenanthroline, phenazine,phenarsazine, phenothiazine, furazan, phenoxazine, pyrrolidine, oxolane,thiolane, oxazole, piperidine, piperazine, morpholine, lactones, lactamssuch as azetidinones and pyrrolidinones, sultams, sultones, and thelike. The heterocyclic ring may be substituted at one or more positionswith such substituents as described above, as for example, halogen,alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, amino, nitro,sulfhydryl, imino, amido, phosphonate, phosphinate, carbonyl, carboxyl,silyl, ether, alkylthio, sulfonyl, ketone, aldehyde, ester, aheterocyclyl, an aromatic or heteroaromatic moiety, —CF₃, —CN, or thelike.

The terms “amine” and “amino” are art-recognized and refer to bothunsubstituted and substituted amines, e.g., a moiety that may berepresented by the general formulas:

wherein R50, R51 and R52 each independently represent a hydrogen, analkyl, an alkenyl, —(CH₂)_(m)—R61, or R50 and R51, taken together withthe N atom to which they are attached complete a heterocycle having from4 to 8 atoms in the ring structure; R61 represents an aryl, acycloalkyl, a cycloalkenyl, a heterocycle or a polycycle; and m is zeroor an integer in the range of 1 to 8. In other embodiments, R50 and R51(and optionally R52) each independently represent a hydrogen, an alkyl,an alkenyl, or —(CH₂)_(m)—R61. Thus, the term “alkylamine” includes anamine group, as defined above, having a substituted or unsubstitutedalkyl attached thereto, i.e., at least one of R50 and R51 is an alkylgroup.

The term “acylamino” is art-recognized and refers to a moiety that maybe represented by the general formula:

wherein R50 is as defined above, and R54 represents a hydrogen, analkyl, an alkenyl or —(CH₂)_(m)—R61, where m and R61 are as definedabove.

The term “amido” is art recognized as an amino-substituted carbonyl andincludes a moiety that may be represented by the general formula:

wherein R50 and R51 are as defined above. Certain embodiments of theamide in the present invention will not include imides which may beunstable.

The term “amidine” refers to moieties that can be represented by theformula:

wherein R₁, R₂, R₃, and R₄ each independently is a hydrocarbon moietycomprised of carbon chains or rings of up to 26 carbon atoms to whichhydrogen atoms are attached. The term includes alkyl, cycloalkyl,alkenyl, alkynyl, and aryl groups, groups which have a mixture ofsaturated and unsaturated bonds, carbocyclic rings, and includescombinations of such groups. In certain embodiments R₁ and R₄, R₂ andR₃, or both (R₁ and R₄) and (R₂ and R₃) taken together with the N atomto which they are attached complete a heterocycle having from 4 to 8atoms in the ring structure.

The term “amidinium” refers to moieties that can be represented by theformula:

wherein R₁, R₂, R₃, and R₄ each independently is a hydrocarbon moietycomprised of carbon chains or rings of up to 26 carbon atoms to whichhydrogen atoms are attached. The term includes alkyl, cycloalkyl,alkenyl, alkynyl, and aryl groups, groups which have a mixture ofsaturated and unsaturated bonds, carbocyclic rings, and includescombinations of such groups. In certain embodiments R₁ and R₄, R₂ andR₃, or both (R₁ and R₄) and (R₂ and R₃) taken together with the N atomto which they are attached complete a heterocycle having from 4 to 8atoms in the ring structure.

The term “carboxyl” is art recognized and includes such moieties as maybe represented by the general formulas:

wherein X50 is a bond or represents an oxygen or a sulfur, and R55 andR56 represents a hydrogen, an alkyl, an alkenyl, —(CH₂)_(m)—R61 or apharmaceutically acceptable salt, R56 represents a hydrogen, an alkyl,an alkenyl or —(CH₂)_(m)—R61, where m and R61 are defined above. WhereX50 is an oxygen and R55 or R56 is not hydrogen, the formula representsan “ester”. Where X50 is an oxygen, and R55 is as defined above, themoiety is referred to herein as a carboxyl group, and particularly whenR55 is a hydrogen, the formula represents a “carboxylic acid”. Where X50is an oxygen, and R56 is hydrogen, the formula represents a “formate”.In general, where the oxygen atom of the above formula is replaced bysulfur, the formula represents a “thiolcarbonyl” group. Where X50 is asulfur and R55 or R56 is not hydrogen, the formula represents a“thiolester.” Where X50 is a sulfur and R55 is hydrogen, the formularepresents a “thiolcarboxylic acid.” Where X50 is a sulfur and R56 ishydrogen, the formula represents a “thiolformate.” On the other hand,where X50 is a bond, and R55 is not hydrogen, the above formularepresents a “ketone” group. Where X50 is a bond, and R55 is hydrogen,the above formula represents an “aldehyde” group.

The term “carbamate” refers to moieties as can be represented by theformula:

wherein R′ is a hydrocarbon moiety comprised of carbon chains or ringsof up to 26 carbon atoms to which hydrogen atoms are attached. The termincludes alkyl, cycloalkyl, alkenyl, alkynyl, and aryl groups, groupswhich have a mixture of saturated and unsaturated bonds, carbocyclicrings, and includes combinations of such groups. It may refer tostraight chain, branched-chain, cyclic structures, or combinationsthereof.

The term “dithiocarbamate” refers to moieties as can be represented bythe formula:

wherein R′ is a hydrocarbon moiety comprised of carbon chains or ringsof up to 26 carbon atoms to which hydrogen atoms are attached. The termincludes alkyl, cycloalkyl, alkenyl, alkynyl, and aryl groups, groupswhich have a mixture of saturated and unsaturated bonds, carbocyclicrings, and includes combinations of such groups. It may refer tostraight chain, branched-chain, cyclic structures, or combinationsthereof.

The definition of each expression, e.g. alkyl, m, n, and the like, whenit occurs more than once in any structure, is intended to be independentof its definition elsewhere in the same structure.

The abbreviations Me, Et, Ph, Tf, Nf, Ts, and Ms represent methyl,ethyl, phenyl, trifluoromethanesulfonyl, nonafluorobutanesulfonyl,p-toluenesulfonyl and methanesulfonyl, respectively. A morecomprehensive list of the abbreviations utilized by organic chemists ofordinary skill in the art appears in the first issue of each volume ofthe Journal of Organic Chemistry; this list is typically presented in atable entitled Standard List of Abbreviations.

Certain compounds contained in compositions of the present invention mayexist in particular geometric or stereoisomeric forms. In addition,polymers of the present invention may also be optically active. Thepresent invention contemplates all such compounds, including cis- andtrans-isomers, R- and S-enantiomers, diastereomers, (D)-isomers,(L)-isomers, the racemic mixtures thereof, and other mixtures thereof,as falling within the scope of the invention. Additional asymmetriccarbon atoms may be present in a substituent such as an alkyl group. Allsuch isomers, as well as mixtures thereof, are intended to be includedin this invention.

If, for instance, a particular enantiomer of compound of the presentinvention is desired, it may be prepared by asymmetric synthesis, or byderivation with a chiral auxiliary, where the resulting diastereomericmixture is separated and the auxiliary group cleaved to provide the puredesired enantiomers. Alternatively, where the molecule contains a basicfunctional group, such as amino, or an acidic functional group, such ascarboxyl, diastereomeric salts are formed with an appropriateoptically-active acid or base, followed by resolution of thediastereomers thus formed by fractional crystallization orchromatographic means well known in the art, and subsequent recovery ofthe pure enantiomers.

It will be understood that “substitution” or “substituted with” includesthe implicit proviso that such substitution is in accordance withpermitted valence of the substituted atom and the substituent, and thatthe substitution results in a stable compound, e.g., which does notspontaneously undergo transformation such as by rearrangement,cyclization, elimination, or other reaction.

The term “substituted” is also contemplated to include all permissiblesubstituents of organic compounds. In a broad aspect, the permissiblesubstituents include acyclic and cyclic, branched and unbranched,carbocyclic and heterocyclic, aromatic and nonaromatic substituents oforganic compounds. Illustrative substituents include, for example, thosedescribed herein above. The permissible substituents may be one or moreand the same or different for appropriate organic compounds. Forpurposes of this invention, the heteroatoms such as nitrogen may havehydrogen substituents and/or any permissible substituents of organiccompounds described herein which satisfy the valences of theheteroatoms. This invention is not intended to be limited in any mannerby the permissible substituents of organic compounds.

For purposes of this invention, the chemical elements are identified inaccordance with the Periodic Table of the Elements, CAS version,Handbook of Chemistry and Physics, 67th Ed., 1986-87, inside cover.

Compounds of the Invention

In certain embodiments, the invention relates to a salt represented by:

wherein

-   -   R₁ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₂ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)—C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₃ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₄ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂)_(n)—NH₂;    -   R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂)_(n)—NH₂;    -   Y represents independently for each occurrence O or S;    -   R₈ represents independently for each occurrence —(CH₂)_(n)—CH₃,        cycloalkyl, aryl, or heteroaryl; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   R₁ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₂ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₃ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₄ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; and    -   R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   R₁ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₂ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₃ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₄ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   R₁ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₂ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₃ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₄ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   Y is O.

In certain embodiments, the invention relates to the aforementionedsalt, wherein Y is O.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is O; and    -   R₁, R₃, and R₄ are methyl.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is O;    -   R₁, R₃, and R₄ are methyl; and    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is O;    -   R₁, R₃, and R₄ are methyl; and    -   R₂ represents n-C₄H₉, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is O;    -   R₁, R₃, and R₄ are methyl;    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇; and    -   R₅ is H.

In certain embodiments, the invention relates to the aforementionedsalt, wherein R₁, R₃, and R₄ are methyl;

-   -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇;    -   Y is O;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ is n-C₈H₁₇;    -   Y is O;    -   R₅ is H; and    -   R₆ represents n-C₄H₉ or n-C₈H₁₇.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   R₁ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₂ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₃ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₄ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   Y is S.

In certain embodiments, the invention relates to the aforementionedsalt, wherein Y is S.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is O; and    -   R₁, R₃, and R₄ are methyl.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is S;    -   R₁, R₃, and R₄ are methyl; and    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is S;    -   R₁, R₃, and R₄ are methyl; and    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is S;    -   R₁, R₃, and R₄ are methyl;    -   R₂ represents n-C₄H₉, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇; and    -   R₅ is H.

In certain embodiments, the invention relates to the aforementionedsalt, wherein R₁, R₃, and R₄ are methyl;

-   -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇;    -   Y is S;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ is n-C₈H₁₇;    -   Y is S;    -   R₅ is H; and    -   R₆ represents n-C₄H₉ or n-C₈H₁₇.

In certain embodiments, the invention relates to the aforementionedsalt, wherein said salt is represented by

In certain embodiments, the invention relates to the aforementionedsalt, wherein said salt is represented by

In certain embodiments, the invention relates to the aforementionedsalt, wherein said salt is represented by

In certain embodiments, the invention relates to the aforementionedsalt, wherein said salt is represented by

In certain embodiments, the invention relates to the aforementionedsalt, wherein said salt is represented by

In certain embodiments, the invention relates to the aforementionedsalt, wherein said salt is represented by

wherein R₆ is represented by n-C₈H₁₇ or n-C₁₈H₃₇.

In certain embodiments, the invention relates to the aforementionedsalt, wherein said salt is represented by

In certain embodiments, the invention relates to a salt represented by

-   -   wherein    -   R₉ is absent or represents one or more substituents attached to        the ring, each of which is independently selected from the group        consisting of H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, and —(CH₂)_(n)—NH₂;    -   z is zero or an integer in the range of 1 to 3;    -   R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂)_(n)—NH₂;    -   R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂)_(n)—NH₂;    -   Y represents independently for each occurrence O or S;    -   R₈ represents independently for each occurrence —(CH₂)_(n)—CH₃,        cycloalkyl, aryl, or heteroaryl; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   R₉ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; and    -   R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   R₉ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   R₉ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   Y is O.

In certain embodiments, the invention relates to the aforementionedsalt, wherein Y is O.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is O; and    -   R₉ is absent.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is O;    -   R₉ is absent; and    -   z is 0 or 1.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is O;    -   R₉ is absent;    -   z is 0 or 1; and    -   R₅ is H.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is O;    -   R₉ is absent;    -   z is 0 or 1;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is O;    -   R₉ is absent;    -   z is 0 or 1;    -   R₅ is H; and    -   R₆ represents n-C₄H₉ or —C₂H₄NH₂.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   R₉ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   Y is S.

In certain embodiments, the invention relates to the aforementionedsalt, wherein Y is S.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is S; and    -   R₉ is absent.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is S;    -   R₉ is absent; and    -   z is 0 or 1.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is S;    -   R₉ is absent;    -   z is 0 or 1; and    -   R₅ is H.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is S;    -   R₉ is absent;    -   z is 0 or 1;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is S;    -   R₉ is absent;    -   z is 0 or 1;    -   R₅ is H; and    -   R₆ represents n-C₄H₉ or —C₂H₄NH₂.

In certain embodiments, the invention relates to the aforementionedsalt, wherein said salt is represented by

In certain embodiments, the invention relates to the aforementionedsalt, wherein said salt is represented by

In certain embodiments, the invention relates to the aforementionedsalt, wherein said salt is represented by

In certain embodiments, the invention relates to the aforementionedsalt, wherein said salt is represented by

In certain embodiments, the invention relates to the aforementionedsalt, wherein said salt is represented by

In certain embodiments, the invention relates to the aforementionedsalt, wherein said salt is represented by

wherein R₆ is represented by n-C₈H₁₇ or n-C₁₈H₃₇.

In certain embodiments, the invention relates to the aforementionedsalt, wherein said salt is represented by

In certain embodiments, the invention relates to a salt represented by:

-   -   wherein    -   R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂)_(n)—NH₂;    -   R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, —(CH₂)_(n)—NH₂;    -   Y represents independently for each occurrence O or S;    -   R₈ represents independently for each occurrence —(CH₂)_(n)—CH₃,        cycloalkyl, aryl, or heteroaryl; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; and    -   R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   Y is O.

In certain embodiments, the invention relates to the aforementionedsalt, wherein Y is O.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is O; and    -   R₅ is H.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is O;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is O;    -   R₅ is H; and    -   R₆ represents n-C₄H₉ or —C₂H₄NH₂.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   Y is S.

In certain embodiments, the invention relates to the aforementionedsalt, wherein Y is S.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is S; and    -   R₅ is H.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is S;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedsalt, wherein

-   -   Y is S;    -   R₅ is H; and    -   R₆ represents n-C₄H₉ or —C₂H₄NH₂.

Methods of the Invention

In certain embodiments, the invention relates to a method of preparing asalt, comprising the step of contacting a gas with a first compound anda second compound, wherein said first compound is selected from thegroup consisting of

-   -   wherein    -   R₁ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₂ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₃ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₄ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₈ represents independently for each occurrence —(CH₂)_(n)—CH₃,        cycloalkyl, aryl, or heteroaryl; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive;    -   R₉ is absent or represents one or more substituents attached to        the ring, each of which is independently selected from the group        consisting of H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, and —(CH₂)_(n)—NH₂;    -   z is zero or an integer in the range of 1 to 3; and    -   said second compound is represented by

-   -   wherein    -   R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂)_(n)—NH₂;    -   R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₈ represents independently for each occurrence —(CH₂)_(n)—CH₃,        cycloalkyl, aryl, or heteroaryl;    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   said gas is represented by:

Y═X═Y

-   -   wherein    -   X represents C or N; and    -   Y represents independently for each occurrence O or S.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₂ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₃ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₄ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, or —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; and    -   R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₂ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₃ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₄ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈; —CH(R₈)₂, or —C(R₈)₃; and    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₂ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₃ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₄ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   Y is O.

In certain embodiments, the invention relates to the aforementionedmethod, wherein said second compound is represented by

In certain embodiments, the invention relates to the aforementionedmethod, wherein said second compound is represented by

In certain embodiments, the invention relates to the aforementionedmethod, wherein said second compound is selected from the groupconsisting of prolinol, leucinol, isoleucinol, valinol, andnorephedrine.

In certain embodiments, the invention relates to the aforementionedmethod, wherein said second compound is represented by

In certain embodiments, the invention relates to the aforementionedmethod, wherein said second compound is represented by

In certain embodiments, the invention relates to the aforementionedmethod, wherein said second compound is selected from the groupconsisting of leucine octyl ester, isoleucine octyl ester, leucineoctadecyl ester, and isoleucine octadecyl ester.

In certain embodiments, the invention relates to the aforementionedmethod, wherein said second compound is selected from the groupconsisting of leucine proline methyl ester, leucine methyl ester, andisoleucine methyl ester.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is S;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁, R₃, and R₄ are methyl;

R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇;

-   -   X is C;    -   Y is S;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C; and    -   Y is O.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O; and    -   R₁, R₃, and R₄ are methyl.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₁, R₃, and R₄ are methyl; and    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₁, R₃, and R₄ are methyl; and    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₁, R₃, and R₄ are methyl;    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇; and    -   R₅ is H.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇;    -   X is C;    -   Y is O;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ is n-C₈H₁₇;    -   X is C;    -   Y is O;    -   R₅ is H; and    -   R₆ represents n-C₄H₉ or n-C₈H₁₇.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₉ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; and    -   R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₉ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₉ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   X is C; and    -   Y is O.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O; and    -   R₉ is absent.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₉ is absent; and    -   z is 0 or 1.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₉ is absent;    -   z is 0 or 1; and    -   R₅ is H.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₉ is absent;    -   z is 0 or 1;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₉ is absent;    -   z is 0 or 1;    -   R₅ is H; and    -   R₆ represents n-C₄H₉ or —C₂H₄NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇;    -   X is C;    -   Y is O;    -   z is 0 or 1;    -   R₅ is H;    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂; and    -   R₉ is absent.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇;    -   X is C;    -   Y is O;    -   z is 0 or 1;    -   R₅ is H;    -   R₆ represents n-C₄H₉ or n-C₆H₁₃; and    -   R₉ is absent.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ is n-C₈H₁₇;    -   X is C;    -   Y is O;    -   z is 0 or 1;    -   R₅ is H;    -   R₆ represents n-C₄H₉ or n-C₆H₁₃; and    -   R₉ is absent.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₉ is absent; and    -   z is 1.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₉ is absent;    -   z is 1; and    -   R₅ is H.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₉ is absent;    -   z is 1;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₉ is absent;    -   z is 1;    -   R₅ is H; and    -   R₆ represents n-C₄H₉ or —C₂H₄NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇;    -   X is C;    -   Y is O;    -   z is 1;    -   R₅ is H;    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂; and    -   R₉ is absent.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇;    -   X is C;    -   Y is O;    -   z is 1;    -   R₅ is H;    -   R₆ represents n-C₄H₉ or n-C₆H₁₃; and    -   R₉ is absent.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ is n-C₈H₁₇;    -   X is C;    -   Y is O;    -   z is 1;    -   R₅ is H;    -   R₆ represents n-C₄H₉ or n-C₆H₁₃; and    -   R₉ is absent.

In certain embodiments, the invention relates to a method comprising thestep of contacting a first gas with an ionic liquid, thereby generatinga second gas; wherein said ionic liquid is represented by:

-   -   wherein    -   said first gas is an inert gas;    -   said second gas is CO₂ or CS₂;    -   R₁ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₂ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₃ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₄ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂)_(n)—NH₂;    -   R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂)_(n)—NH₂;    -   Y represents independently for each occurrence O or S;    -   R₈ represents independently for each occurrence —(CH₂)_(n)—CH₃,        cycloalkyl, aryl, or heteroaryl;    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   R₁ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₂ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₃ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₄ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; and    -   R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   R₁ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₂ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₃ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₄ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   R₁ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₂ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —CH(R₈)₂, or —C(R₈)₃;    -   R₃ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₄ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   Y is O.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen; and    -   Y is O.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   Y is O; and    -   R₁, R₃, and R₄ are methyl.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   Y is O;    -   R₁, R₃, and R₄ are methyl; and    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   Y is O;    -   R₁, R₃, and R₄ are methyl; and    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   Y is O;    -   R₁, R₃, and R₄ are methyl;    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇; and    -   R₅ is H.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   R₁, R₃, and R₄ are methyl,    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇;    -   Y is O;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   R₁, R₃, and R₄ are methyl;    -   R₂ is n-C₈H₁₇;    -   Y is O;    -   R₅ is H; and    -   R₆ represents n-C₄H₉ or n-C₈H₁₇.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   R₁ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₂ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₃ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₄ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   Y is S.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen; and    -   Y is S.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   Y is S; and    -   R₁, R₃, and R₄ are methyl.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   Y is S;    -   R₁, R₃, and R₄ are methyl; and    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   Y is S;    -   R₁, R₃, and R₄ are methyl; and    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   Y is S;    -   R₁, R₃, and R₄ are methyl;    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇; and    -   R₅ is H.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   R₁, R₃, and R₄ are methyl,    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇;    -   Y is S;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   R₁, R₃, and R₄ are methyl;    -   R₂ is n-C₈H₁₇;    -   Y is S;    -   R₅ is H; and    -   R₆ represents n-C₄H₉ or n-C₈H₁₇.

In certain embodiments, the invention relates to the aforementionedmethod, wherein said ionic liquid is represented by

In certain embodiments, the invention relates to the aforementionedmethod, wherein said ionic liquid is represented by

In certain embodiments, the invention relates to the aforementionedmethod, wherein said ionic liquid is represented by

In certain embodiments, the invention relates to the aforementionedmethod, wherein said ionic liquid is represented by

In certain embodiments, the invention relates to the aforementionedmethod, wherein said ionic liquid is represented by

In certain embodiments, the invention relates to the aforementionedmethod, wherein said ionic liquid is represented by

wherein R₆ is represented by n-C₈H₁₇ or n-C₁₈H₃₇.

In certain embodiments, the invention relates to the aforementionedmethod, wherein said ionic liquid is represented by

In certain embodiments, the invention relates to a method comprising thestep of contacting a first gas with an ionic liquid, thereby generatinga second gas; wherein said ionic liquid is represented by:

-   -   wherein    -   said first gas is an inert gas;    -   said second gas is CO₂ or CS₂;    -   R₉ is absent or represents one or more substituents attached to        the ring, each of which is independently selected from the group        consisting of H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR_(B), —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, and —(CH₂), —NH₂;    -   z is zero or an integer in the range of 1 to 3;    -   R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂), —NH₂;    -   R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂)_(n)—NH₂;    -   Y represents independently for each occurrence O or S;    -   R₈ represents independently for each occurrence —(CH₂)_(n)—CH₃,        cycloalkyl, aryl, or heteroaryl; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   R₉ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   R₉ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   R₉ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   Y is O.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen; and    -   Y is O.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   Y is O; and    -   R₉ is absent.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   Y is O;    -   R₉ is absent; and    -   z is 0 or 1.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   Y is O;    -   R₉ is absent;    -   z is 0 or 1; and    -   R₅ is H.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   Y is O;    -   R₉ is absent;    -   z is 0 or 1;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   Y is O;    -   R₉ is absent;    -   z is 0 or 1;    -   R₅ is H; and    -   R₆ represents n-C₄H₉ or —C₂H₄NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   R₉ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   Y is S.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen; and    -   Y is S.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   Y is S; and    -   R₉ is absent.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   Y is S;    -   R₉ is absent; and    -   z is 0 or 1.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   Y is S;    -   R₉ is absent;    -   z is 0 or 1; and    -   R₅ is H.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   Y is S;    -   R₉ is absent;    -   z is 0 or 1;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   said first gas is nitrogen;    -   Y is S;    -   R₉ is absent;    -   z is 0 or 1;    -   R₅ is H; and    -   R₆ represents n-C₄H₉ or —C₂H₄NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein said ionic liquid is represented by

In certain embodiments, the invention relates to the aforementionedmethod, wherein said ionic liquid is represented by

In certain embodiments, the invention relates to the aforementionedmethod, wherein said ionic liquid is represented by

In certain embodiments, the invention relates to the aforementionedmethod, wherein said ionic liquid is represented by

In certain embodiments, the invention relates to the aforementionedmethod, wherein said ionic liquid is represented by

In certain embodiments, the invention relates to the aforementionedmethod, wherein said ionic liquid is represented by

wherein R₆ is represented by n-C₈H₁₇ or n-C₁₈H₃₇.

In certain embodiments, the invention relates to the aforementionedmethod, wherein said ionic liquid is represented by

In certain embodiments, the invention relates to a method of removing agas from a mixture, comprising the step of contacting said mixture witha first compound and a second compound, wherein said first compound isselected from the group consisting of

-   -   wherein    -   R₁ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₂ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₃ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₄ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₈ represents independently for each occurrence —(CH₂)_(n)—CH₃,        cycloalkyl, aryl, or heteroaryl; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive;    -   R₉ is absent or represents one or more substituents attached to        the ring, each of which is independently selected from the group        consisting of H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂)_(n)—NH₂;    -   z is zero or an integer in the range of 1 to 3; and    -   said second compound is represented by

-   -   wherein    -   R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂)_(n)—NH₂;    -   R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,        —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,        —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈,        —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂)_(n)—NH₂;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   said gas is represented by:

Y═X═Y

-   -   wherein    -   X represents C or N; and    -   Y represents independently for each occurrence O or S.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₂ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₃ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₄ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, or —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; and    -   R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₂ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₃ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₄ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₂ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₃ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₄ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   Y is O.

In certain embodiments, the invention relates to the aforementionedmethod, wherein said second compound is represented by

In certain embodiments, the invention relates to the aforementionedmethod, wherein said second compound is represented by

In certain embodiments, the invention relates to the aforementionedmethod, wherein said second compound is selected from the groupconsisting of prolinol, leucinol, isoleucinol, valinol, andnorephedrine.

In certain embodiments, the invention relates to the aforementionedmethod, wherein said second compound is represented by

In certain embodiments, the invention relates to the aforementionedmethod, wherein said second compound is represented by

In certain embodiments, the invention relates to the aforementionedmethod, wherein said second compound is selected from the groupconsisting of leucine octyl ester, isoleucine octyl ester, leucineoctadecyl ester, and isoleucine octadecyl ester.

In certain embodiments, the invention relates to the aforementionedmethod, wherein said second compound is selected from the groupconsisting of leucine proline methyl ester, leucine methyl ester, andisoleucine methyl ester.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is S;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇;    -   X is C;    -   Y is S;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C; and    -   Y is O.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O; and    -   R₁, R₃, and R₄ are methyl.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₁, R₃, and R₄ are methyl; and    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₁, R₃, and R₄ are methyl; and    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₁, R₃, and R₄ are methyl;    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇; and    -   R₅ is H.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇;    -   X is C;    -   Y is O;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ is n-C₈H₁₇;    -   X is C;    -   Y is O;    -   R₅ is H; and    -   R₆ represents n-C₄H₉ or n-C₈H₁₇.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₉ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; and    -   R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,        alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,        —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, C≡CR₈, —CH(R₈)₂, or —C(R₈)₃.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₉ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₉ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,        heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃;    -   X is C; and    -   Y is O.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O; and    -   R₉ is absent.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₉ is absent; and    -   z is 0 or 1.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₉ is absent;    -   z is 0 or 1; and    -   R₅ is H.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₉ is absent;    -   z is 0 or 1;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₉ is absent;    -   z is 0 or 1;    -   R₅ is H; and    -   R₆ represents n-C₄H₉ or —C₂H₄NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇;    -   X is C;    -   Y is O;    -   z is 0 or 1;    -   R₅ is H;    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂; and    -   R₉ is absent.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇;    -   X is C;    -   Y is O;    -   z is 0 or 1;    -   R₅ is H;    -   R₆ represents n-C₄H₉ or n-C₆H₁₃; and    -   R₉ is absent.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ is n-C₈H₁₇;    -   X is C;    -   Y is O;    -   z is 0 or 1;    -   R₅ is H;    -   R₆ represents n-C₄H₉ or n-C₆H₁₃; and    -   R₉ is absent.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₉ is absent; and    -   z is 1.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₉ is absent;    -   z is 1; and    -   R₅ is H.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₉ is absent;    -   z is 1;    -   R₅ is H; and    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   X is C;    -   Y is O;    -   R₉ is absent;    -   z is 1;    -   R₅ is H; and    -   R₆ represents n-C₄H₉ or —C₂H₄NH₂.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇;    -   X is C;    -   Y is O;    -   z is 1;    -   R₅ is H;    -   R₆ represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃,        n-C₈H₁₇, —C₂H₄NH₂, or —C₆H₁₂NH₂; and    -   R₉ is absent.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ represents n-C₄H₉, n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇;    -   X is C;    -   Y is O;    -   z is 1;    -   R₅ is H;    -   R₆ represents n-C₄H₉ or n-C₆H₁₃; and    -   R₉ is absent.

In certain embodiments, the invention relates to the aforementionedmethod, wherein

-   -   R₁, R₃, and R₄ are methyl;    -   R₂ is n-C₈H₁₇;    -   X is C;    -   Y is O;    -   z is 1;    -   R₅ is H;    -   R₆ represents n-C₄H₉ or n-C₆H₁₃; and    -   R₉ is absent.

EXEMPLARY EMBODIMENTS (i). Compounds

Useful compounds will be described below using various formulas. In eachcase, the variables in the formula are defined specifically for eachindividual formula. A definition of a variable for one formula shouldnot be used to vary a definition provided for another formula, althougha variable that has not been defined for one formula may be interpretedby analogy with a definition elsewhere for a similar formula.

Variations, modifications, and other implementations of what isdescribed herein will occur to those of ordinary skill without departingfrom the spirit and the scope of the invention. Accordingly, theinvention is not to be limited only to the preceding illustrativedescription. For additional illustrative features that may be used withthe invention, including the embodiments described here, refer to thedocuments listed herein above and incorporated by reference in theirentirety. All operative combinations between the above describedillustrative embodiments and those features described below areconsidered to be potentially patentable embodiments of the invention.

Exemplification

The invention now being generally described, it will be more readilyunderstood by reference to the following examples which are includedmerely for purposes of illustration of certain aspects and embodimentsof the present invention, and are not intended to limit the invention.

Example 1 N,N-Dimethyl-N′-butyl Ethanimidamide (A or C4)

Dimethylcarbamyl chloride (9.35 g, 86.9 mmol) was slowly added to asolution of N-hexyl acetamide (10.0 g, 86.9 mmol) in 10 mL of drytoluene. After being refluxed under a nitrogen atmosphere for 16 h, thevolatile materials were removed on a rotary evaporator and then in vacuofor 2 h at room temperature. The residue was dissolved in 30 mLdichloromethane and the solution was stirred vigorously with a solutionof 3.48 g (86.9 mmol) of sodium hydroxide in 40 mL water for 30 min.Calcium carbonate (3.48 g) was added to the mixture and it was stirredanother 30 min. The organic phase was separated and the aqueous phasewas washed with dichloromethane (3×25 mL). The combined organic phaseswere dried over anhydrous calcium carbonate. The volatile materials wereevaporated on a rotary evaporator. The residue was distilled, by 28-30°C./0.25 Torr (lit. bp 69-71° C./13 Torr (see Haug, E. et al. Synthesis,1983, 35-37)), to yield 4.0 g (32%) of product, 98% pure (GC). IR (neat)2956, 2929, 286 (C—H), 1629 (N═C) cm⁻¹. ¹H NMR 3.17 (t, 2H, J_(HH) 7.2Hz, —CH₂—N═), 2.86 (s, 6H, —N—(CH₃)₂); 1.87 (s, 3H, —N═C(CH₃)—N); 1.5(m, 2H, —CH—CH₂—N═); 1.25-1.4 (m, 6H, CH₃—(CH)₃—); 0.88 (t, 3H, J_(HH)7.2 Hz, CH₃).

Example 2 N,N-Dimethyl-N′-amyl ethanimidamide (B or C5)

N-Hexyl acetamide (10.0 g, 77.5 mmol) was added 10 mL of dry toluene,then 8.33 g (77.5 mmol) of dimethylcarbamyl chloride was slowly addedand then refluxed under a nitrogen atmosphere for 16 h. The volatilematerials were removed on a rotary evaporator and then in vacuo at roomtemperature. The residue was dissolved dichloromethane (30 mL) and 3.1 g(77.5 mmol) of sodium hydroxide dissolved aqueous solution (40 mL) wasadded. The mixture was stirred vigorously for 30 min. Calcium carbonate(3.1 g) was added to the mixture and it was stirred another 30 min. Theorganic phase was separated and the aqueous phase was washed withdichloromethane (3×25 mL). The combined organic liquids were dried(calcium carbonate) and the volatile materials were removed on a rotaryevaporator. The residue was distilled at 40-41° C./0.25 Torr to yield4.7 g (39%) of product (98.5% pure by GC). IR (neat) 2956, 2927, 2857(C—H), 1626 (N═C) cm⁻¹. ¹H NMR 3.18 (t, 2H, J_(HH) 7.5 Hz, —CH₂—N═),2.87 (s, 6H, —N—(CH₃)₂); 1.88 (s, 3H, —N═C(CH₃)—N); 1.51 (m, 2H,—CH—CH₂—N═); 1.25-1.4 (m, 4H, CH₃—(CH₂)₂—); 0.90 (t, 3H, J_(HH) 6.9 Hz,CH₃). ¹³C NMR 158.90; 50.35; 38.15; 32.27; 29.98; 22.87; 14.31; 12.53.

Example 3 N,N-Dimethyl-N′-hexyl Ethanimidamide (C or C6)

To a solution of N-hexyl acetamide (15.0 g, 105 mmol) in 15 mL of drytoluene was slowly added 11.2 g (104.9 mmol) of dimethylcarbamylchloride. The solution was refluxed under a nitrogen atmosphere for 24h. The volatile materials were removed on a rotary evaporator and thenin vacuo at room temperature. The residue was dissolved 30 mL ofchloroform and stirred vigorously with a solution of 4.2 g sodiumhydroxide in 40 mL of water for 30 min. Calcium carbonate (4.2 g) wasadded and stirring was continued for another 30 min. The organic phasewas separated and the aqueous phase was extracted with dichloromethane(25 mL×3). The combined organic phases were dried (calcium carbonate)and the solvent was removed on a rotary evaporator. The residue wasdistilled at 52-54° C./0.25 Torr (lit. bp 125° C./30 Torr (seeOszczapowicz, J.; Raczynska, E. J. Chem. Soc., Perkin Trans. 2 1984,1643-1666)) product to yield 8.7 g (49%) of liquid (purity 99% by GC).IR (neat) 2955, 2926, 2856 (C—H), 1626 (N═C) cm⁻¹. ¹H NMR 3.18 (t, 2H,J_(HH) 7.5 Hz, —CH₂—N═), 2.87 (s, 6H, —N—(CH₃)₂); 1.87 (s, 3H,—N═C(CH₃)—N); 1.49 (m, 2H, —CH₂—CH₂—N═); 1.25-1.4 (m, 6H, CH₃—(CH₂)₃—);0.88 (t, 3H, J_(HH) 7.2 Hz, CH₃). ¹³C NMR 158.79; 50.32; 38.07; 32.49;32.00; 27.38; 22.80; 14.17; 12.45.

Example 4 N,N-Dimethyl-N′-heptyl Ethanimidamide (D or C7)

Dimethylcarbamyl chloride (6.86 g, 63.7 mmol) was added slowly to 10.0 g(63.7 mmol) of N-octyl acetamide in 10 mL of dry toluene and thesolution was refluxed under a nitrogen atmosphere for 16 h. The volatilematerials were removed on a rotary evaporator in vacuo. The residue,dissolved 30 mL of dichloromethane, was stirred vigorously with asolution of 2.55 g (63.7 mmol) of sodium hydroxide in 40 mL of water for30 min. Calcium carbonate (2.55 g) was added to the mixture and stirringwas continued for an additional 30 min. The organic phase was separatedand the aqueous phase was extracted with dichloromethane (30 mL×3). Thecombined organic phases were dried (calcium carbonate) and the solventwas removed on a rotary evaporator. The residue was distilled at 63-64°C./0.25 Torr to yield 6.2 g (53%) of product (purity 99% by GC). IR2956, 2925, 2854 (C—H), 1626 (N═C) cm⁻¹. ¹H NMR 3.17 (t, 2H, J_(HH) 7.5Hz, —CH₂—N═), 2.86 (s, 6H, —N—(CH₃)₂); 1.87 (s, 3H, —N═C(CH₃)—N); 1.5(m, 2H, —CH—CH₂—N═); 1.25-1.4 (m, 10H, CH₃—(CH₂)₅—); 0.88 (t, 3H, J_(HH)7.2 Hz, CH₃).

Example 5 N,N-Dimethyl-N′-octyl Ethanimidamide (E or C8)

Dimethylcarbamyl chloride (6.29 g, 58.4 mmol) was added slowly to 10.0 g(58.4 mmol) of N-octyl acetamide in 10 mL of dry toluene and thesolution was refluxed under a nitrogen atmosphere for 16 h. The volatilematerials were removed on a rotary evaporator and in vacuo. The residue,dissolved dichloromethane (30 mL), was stirred strongly for 30 min witha solution of 2.34 g (58.4 mmol) of sodium hydroxide in 40 mL of water.Calcium carbonate (2.34 g) was added to the mixture and it was stirredan additional 30 min. The organic phase was separated and the aqueousphase was washed with dichloromethane (30 mL×3). The combined organicphases were dried (calcium carbonate) and the volatile materials wereremoved on a rotary evaporator. The residue was distilled at 72-77°C./0.25 Torr to yield 7.1 g (61%) of product (purity 99% by GC). IR(neat) 2955, 2924, 2853 (C—H), 1627 (N═C) cm⁻¹. ¹H NMR 3.17 (t, 2H,J_(HH) 6.9 Hz, —CH₂—N═), 2.86 (s, 6H, —N—(CH₃)₂); 1.87 (s, 3H,—N═C(CH₃)—N); 1.5 (m, 2H, —CH₂—CH₂—N═); 1.25-1.4 (m, 10H, CH₃—(CH₂)₅—);0.88 (t, 3H, J_(HH) 6.1 Hz, CH₃).

Example 6 1-(p-Dimethylaminophenyl)-2-nitroethylene (DAPNE)

A mixture of 4-dimethylaminobenzaldehyde (1.5 g, 10 mmol) in 3 mLmethanol, 0.61 g (10 mmol) nitrobenzene and 0.15 mL of 22% methylamineaqueous solution was stirred for 3 days. The dark red solid obtainedafter filtration was recrystallized from nitromethane and rinsed withcold methanol to yield 0.79 g (41.1%) of red crystals, mp 180.6-180.9°C. (ref mp 181° C. (see Richter-Egger, D. L. et al. J. Chem. Educ. 2001,78, 1375-1378)). ¹H NMR 3.08 (s, 6H, Ar—N(CH₃)₂); 6.68 (2H, d, J_(HH)8.7 Hz, Ar—H); 7.43 (2H, d, J_(HH) 9.0 Hz, Ar—H); 7.50 (1H, d, J_(HH)13.2 Hz, Ar—CH); 7.97 (1H, d, J_(HH) 13.5 Hz, CH—NO₂).

Example 7 Preparation of Ionic Liquids and their Reconversion toAmidine/Amine Mixtures

Dry CO₂ gas was bubbled for 1 h through a solution of neat amidine andamine in a glass vessel immersed in a room-temperature water bath; theuptake of CO₂ is slightly exothermic. Amidine/1,6-diaminohexane (8)samples were heated until 8 dissolved completely and then CO₂ gas wasbubbled through the sample mixtures.

An aliquot of 0.1 mL of E+5 was added to 0.9 mL of n-decane. Dry CO₂ wasbubbled through the liquid for 30 min. Separation into 2 liquid phases(ca. 0.1 mL and 0.9 mL each) was observed after the cloudy mixture wasallowed to stand undisturbed for some time. Then, N₂ gas was bubbledthrough the mixture for 2.5 h at 24° C. and one clear liquid phase wasobserved again.

Example 8 Measurements of CO₂ Uptake

A burette was filled with CO₂ gas and the apparatus was purged byflushing CO₂ through it for >30 min. Then, a flask with a weighed amountof amidine and amine mixture (neat) was attached to gas burette. Thesample liquid was stirred with a Teflon-coated spin bar and the volumeof CO₂ taken up was recorded as a function of time until no change wasdiscernible. This procedure was repeated 3 times on different aliquotsof each sample.

The percentage of the theoretical amount of CO₂ taken up (% CO₂) wascalculated. The volume of CO₂ taken up by the amine/amidine solution (V)was calculated from eq. 1, where V_(blank) is the amount of volumedecrease in the burette when the flask contained only CO₂ and V_(obs) isthe total volume decrease measured by the burette.

V=(V _(obs) −V _(blank))  (1)

The theoretical volume of CO₂ (V_(P,T)) taken up by M moles ofamidine/amine at a known T (K) and P (Torr), assuming completeconversion to amidinium carbamate, was calculated using eq 2.

V _(P,T)=[22.4×(760/P)×(T/273.15)]×M  (2)

Then,

% CO₂ =[V/V _(P,T)]×100  (3)

The % CO₂ values of hexylamine (5), E+5, C+2 and E+6 are shown below for3 separate experiments. The average is reported in the main text.

% CO₂ of hexy lamine (5) time (min) sample 1 sample 2 sample 3 average1-3 0 0 0 0 0 1 39 43 43 41 2 45 46 44 45 3 47 47 46 47 5 48 47 46 47 1048 47 47 47 15 48 47 47 47 20 48 47 47 47 25 48 47 47 47 30 48 47 47 47

% CO₂ of E + 5 time (min) sample 1 sample 2 sample 3 average 1-3 0 0 0 00 1 41 40 32 38 2 68 57 47 57 3 82 71 63 72 5 91 84 81 85 10 104 99 96100 15 106 104 102 104 20 108 109 106 108 25 108 110 108 109 30 108 111109 110 35 108 112 109 110 40 108 113 110 110 45 108 114 110 111 50 108114 110 111 55 108 115 110 111 60 108 115 110 111

% CO₂ of C + 2 time (min) sample 1 sample 2 sample 3 average 1-3 0 0 0 00 1 73 66 75 71 2 85 84 87 85 3 90 90 94 91 4 94 91 95 93 5 96 94 97 9610 97 96 99 98 15 101 99 102 101 20 103 99 103 102 25 103 100 104 102 30104 101 104 103 35 104 101 104 103 40 105 101 104 103 45 105 101 105 10350 105 101 105 104 55 105 101 105 104 60 106 101 105 104

% CO₂ of E + 6 time (min) sample 1 sample 2 sample 3 average 1-3 0 0 0 00 1 29 27 17 24 2 47 45 33 42 3 52 53 42 49 4 59 59 51 56 5 66 63 55 6110 69 70 67 68 15 71 72 71 71 20 72 75 72 73 25 73 76 72 73 30 73 76 7374 35 73 76 73 74 40 73 76 73 74 45 73 75 72 73 50 73 75 72 73 55 72 7572 73 60 72 75 72 73

Example 9 UV-Vis Spectroscopic Measurements

An aliquot of a methanol solution of DAPNE was transferred into a samplevial and the methanol was removed by blowing N₂ gas over it. Then, analiquot of the solvent of interest was added and stirred until the soliddissolved completely. The concentrations of DAPNE in the solutions were32-162 μM. The absorption spectra were recorded in a 1-mm pathlengthquartz cuvette. The wavelength maxima are collected in the followingtable:

solvent λ_(max) (nm) n-heptane 393^(a) n-decane 396 n-hexy lamine (5)416 E 423 E + 5 423 toluene 425^(a) THF 427 ethanol 431^(a) acetone 433DBU + 1-hexanol 437 E5-C 438 N,N-dimethylformamide (DMF) 446^(a)dimethyl sulfoxide (DMSO) 456 water 496^(a)

^(a)Data from Richter-Egger, D. L.; Tesfal, A.; Flamm, S. J.; Tucker, S.A. J. Chem. Educ. 2001, 78, 1375-1378

The solvatochromic dye, 1-(p-dimethylaminophenyl)-2-nitroethylene(DAPNE), can be used to estimate the polarity of the reversible RTILsystems. Its absorption maximum in E+5 at 423 nm indicates anenvironment slightly less polar than toluene (λ_(max)=425 nm). After CO₂exposure, the E5−C absorption shifted to 438 nm, indicating anenvironment more polar than acetone (λ_(max)=433 nm) and less polar thanN,N-dimethylformamide (DMF) (λ_(max)=446 nm). In general, E5−C appearsto be less polar than other ionic liquids. For example, 1-butyl-3-methylimidazolium hexafluorophosphate is much more polar than DMF based uponE_(T)(30) values.

Chiral Amino Alcohol Systems

Absorption maxima (λ_(max)) of 2.4 mM DAPNE in various solvents andRTILs.

solvent λ_(max) (nm) n-heptane 393 n-decane 396 C8/Hex 423 C8ValOH 424C8/IleC₁ 425 Toluene 425 THF 427 Acetone 433 C8-Hex-C 438 C8-ValOH—C 443C8-IleC1—C 443 DMF 446

Example 10 NMR Spectroscopy

Measured quantities of amidine and amine were dissolved in a knownvolume of CDCl₃. Alternatively, CO₂ and N₂ were bubbled through thesolutions for 30 mM at room temperature. At the end of each bubblingperiod with one gas, NMR spectra were recorded. For the experimentleading to FIG. 4, the N₂ bubbling times were 60 mM.

The chemical shifts of selected ¹H and ¹³C resonances in NMR spectra ofLn−C, but not of the corresponding nuclei in the L+n mixtures, weresensitive to concentration in the range explored, 10-350 mM. A detailedstudy of this concentration effect was conducted in CDCl₃ solutions ofthe E+5/E5−C system (FIG. 4). The nuclei of E most affected are theprotons of the geminal N-dimethyl groups (N═C—N(CH ₃)₂), the C-methylprotons (N═C(CH ₃)—N), the α-methylene protons (—CH ₂N═C—N), and theamidine carbon atom (N═C(CH₃)—N). Upon addition of CO₂ to solutions of10 mM E+5, small shifts were observed, but the system had the samespectral features as in the absence of CO₂. However, infrared spectralstudies conducted with a different amidine-amine pair at 10 mM, showingthe presence of the distinctive IR stretching frequencies of amidiniumand carbamate, and our previous NMR study of the concentrationdependence on chemical shifts of protons and carbon atoms inalkylammonium alkylcarbamates provide strong indirect evidence that E5−Cwas present after bubbling CO₂ even through the 10 mM solution. Theshifts, primarily to lower field, increased with increasing soluteconcentrations upon addition of CO₂ and reached plateau values at ca.100 mM. By bubbling N₂ gas through the solutions with higherconcentrations of E5−C(N.B. 175 mM; FIG. 4), the proton signals could bereturned to their E+5 values; the system was cycled between E+5 andE5−C, with little or no degradation of the sample.

Example 11 IR Spectroscopy

Formation of amidinium carbamate is also evident from the FT-IR spectraof E+5 and E5−C. After CO₂ bubbling, the N═C stretching frequencies ofE+5 at 1629 cm⁻¹ were replaced by bands for E5−C at 1646 and 1575 cm⁻¹which can be assigned to protonated amidine and carbamate stretches.

Example 12 Thermogravimetric Analysis (TGA)

Results from TGA measurements of E+5 and E5−C are included here as anexample (FIG. 2). The plateau above 50° C. corresponds to a loss of12.4% sample weight, in excellent agreement with the calculated CO₂weight loss, 12.8%. The TGA measurements also indicate that some of theamine and amidine components are being evaporated and entrained in thenitrogen wind which the samples experience during the experiments.Regardless, it should be possible to employ the RTIL amidiniumcarbamates above room temperature while retaining their reversibilitywith the non-ionic components in a closed vessel.

Example 13 Room-Temperature Ionic Liquids (RTILs) Comprising Amidinesand Chiral Amino Alcohols

Remarkably, we have discovered room-temperature chiral amidiniumcarbamate ionic liquids derived from amidines and amino-acid alcohols.The major advantages of this system are chiral, reversible, easypreparation, less sensitive to water and further modifiable for specifictask. They are prepared by exposing a 1:1 mixture of an easilysynthesized amidine (N′-alkyl-N,N-dimethylacetamidine; L) and an aminoalcohol (A), obtained from reduction of naturally occurring amino acid,to an atmosphere of CO₂ (C). All of the L/A combinations are liquids atroom temperature, and maintain liquid state even at far below 0° C. Inaddition, L-A-C ionic liquids are able to return to non-ionic stateafter bubbling inert gas, (N₂ or argon), and heating around 50° C. for amore rapid reversion. Amino alcohols comprise chiral centers, modifiablehydroxyl group and may be biodegradable. Six amino alcohols derived fromnaturally occurring amino acids and one commercially available aminoalcohol with two chiral centers, (1S,2S)-norephedrine were studied. Thepresence of a second chiral center in the amino alcohol may increase theability of the chiral L/A phase to act as chiral inductor for guestreactions or in separations.

Materials. Unless stated otherwise, all reagents were used as received.L-Proline (Pro; 99%), L-Leucine (Leu; 99%), L-Isoleucine (Ile; 99%),L-Methionine (Met; 98.5%), L-Phenylalanine (Phe; 98.5%) were from Acros;Triethylamine (99.9%) was from Alfa Aesor; L-Valine (Val; 98%),(1S,2S)-Norephedrine (Nor; 99%), n-Decane (99%) and Lithium aluminiumhydride (LiAlH₄; 95%) were from Aldrich. Methanol (Aldrich, 99.8%) wasdried by Vogel's method. Toluene (Aldrich, 99.9%) was dried by refluxingover sodium metal for 5 h, followed by distillation. Tetrohydrofuran(Acros, 99.9%) was dried by refluxing over sodium metal, followed bydistillation. Carbon dioxide gas, generated by warming dry-ice, wasdried by passing it through a tube filled with indicating Drierite.

Instrumentation. NMR spectra (referenced to internal tetramethylsilane(TMS) for ¹H and to CDCl₃ for ¹³C) were recorded on a Varian 300 MHzspectrometer interfaced to a Sparc UNIX computer using Mercury software.IR spectra were obtained on a Perkin-Elmer Spectrum One FTIRspectrometer interfaced to a PC, using an attenuated total reflectionaccessory or NaCl plates. UV-Vis spectra were recorded on a Varian CARY300 Bio UV-Visible spectrophotometer in Hellma quartz cells with 0.1 mmpath lengths. Thermal gravimetric analysis (TGA) measurements wereperformed under a nitrogen atmosphere at a 5° C./min heating rate on aTGA 2050 thermogravimetric analyzer (TA Instruments) interfaced to acomputer. Gas chromatographic (GC) analyses were performedHewlett-Packard 5890A gas chromatograph equipped with flame ionizationdetectors and a DB-5 (15 m×0.25 mm) column (J & W Scientific, Inc.).GC-MS measurements were obtained on a SHIMADZU GC-17A gas chromatographconnected SHIMADZU QP-5000 mass spectrometer instrument using a 0.25 μmSGE BPX5 (15 m×0.25 mm) column and a flame ionization detector. Opticalrotations were recorded on a Rudolph Instruments DigiPal 781 automaticpolarimeter at 589 nm in Hellma quartz cells with 0.1 mm path lengths.Conductivity was measured with a YSI model 31 conductivity meter. Theconductivity value was calibrated by various concentration of standardKCl solution (H₂0, Millipore, 18.3 mΩ).

Syntheses. The procedure for synthesis of the amino alcohols ispresented in detail for L-Leucinol; minor variations were adopted forthe other amino alcohols.

L-Leucinol (LeuOH). Ten grams of L-Leucine (76.2 mmol) was suspended in100 mL of THF under the nitrogen atmosphere. The suspension was cooledin the ice bath and 4 g of lithium aluminum hydride (100 mmol) was addedover a 30 min period. After the addition was complete, the ice bath wasremoved and the reactant was warmed to room temperature and thenrefluxed for 24 hours under nitrogen. The reactant was quenched withwater (4 mL), then aqueous 15% of sodium hydroxide (4 mL), and water 12mL. The solution was stirred for 30 min and white precipitate isfiltrated. The filter cake was washed with Dichloromethane and thecombined organic layer was dried with sodium sulfate, and concentratedunder reduced pressure (8.7 g., 97%). The L-leucinol was isolated bydistillation. Bp 90° C. (0.9 mm) lit. 64-65° C. (1.5 mm) Yield 5.3 g(59.5%) colorless liquid was obtained. 98% (GC). ¹H NMR: δ 3.56 and 3.23(d-d and t, 2H, CH₂—OH); 3.29 (m, 1H, H₂N—C*H) 1.8-2.4 (br, 3H, NH₂ andOH) 1.68 (m, 1H, CH₂—CH(CH₃)₂); 1.21 (t, 2H, C*H—CH₂—CH); 0.89-0.94 (m,6H, CH(CH₃)₂). ¹³C NMR: δ 67.12, 50.83, 43.68, 24.89, 23.58, 22.38.

L-Prolinol (ProOH). Yield: 48.0% yellowish clear liquid; 99% (GC). Bp46-47° C., (0.2 mm); lit. 89° C., (6 mm); 1H NMR: δ 3.22-3.58 (m, 5H,—NH—C*H—CH₂—OH); 2.90 (t, 2H, —CH₂—CH₂—NH—); 1.65-1.88 and 1.34-1.46 (m,4H, CH₂—CH₂—C*H). ¹³C NMR: δ 64.90, 59.92, 46.50, 27.65, 26.01.

L-Valinol (ValOH). Yield: 50.2% colorless clear solid; 98% (GC). Bp38-39° C., (0.15 mm); lit. 55-57° C., (2 mm); ¹H NMR: δ 3.64 and 3.29(d-d and t, 2H, CH₂—OH), 2.56 (m, 1H, H₂N—C*H); 1.7-2.2 (br, 3H, NH₂ andOH); 1.57 (m, 1H, C*H—CH(CH₃)₂); 0.92 (m, 6H, CH(CH₃)₂). ¹³C NMR: δ64.89, 58.64, 31.71, 19.48, 18.56.

L-Isoleucinol (IleOH). Yield: 53.9% colorless solid was obtained. 98%(GC). Bp 61° C. (0.5 mm), mp 32.5-37.3° C. lit. Bp 100-101° C. (5 mm),mp 38-40° C. ¹H NMR: δ 3.64 and 3.28 (d-d and t, 2H, CH₂—OH); 2.61-2.68(m, 1H, C*H); 1.48-1.57 (m, 1H, C*H—CH—); 1.12-1.39 (m, 2H, CH—CH₂—CH₃);1.87 (br, 3H, NH₂ and OH), 0.87-1.12 (m, 6H, CH(CH₃)—CH₂CH₃). ¹³C NMR: δ64.52, 57.19, 38.79, 25.50, 15.29, 11.48.

L-Methioninol (MetOH). Yield: 83% yellowish clear solid was obtained.99% (GC). ¹H NMR: δ 3.60 and 3.34 (d-d and q, 2H, CH₂—OH); 2.95 (m, 1H,H₂N—C*H); 2.62 (m, 2H, CH₂—S—CH₃); 2.11 (s, 3H, CH₂—S—CH₃); 2.0-2.3 (br,3H, NH₂ and OH) 1.73 and 1.54 (m, 2H, CH₂—CH₂—S—CH₃). ¹³C NMR: δ 66.92,52.16, 33.83, 31.26, 15.83. GC-MS: Calcd for C₅H₁₃NOS, 135; found 136([M+H]⁺).

L-Phenylalaminol (PheOH). Yield: 2.8 g (62%) colorless clear solid wasobtained. 99% (GC). mp 92.5-94.4° C. (lit. 91-93° C.). ¹H NMR: δ 1.64(br, 3H, NH₂ and OH), 2.53 (d-d, 1H, CH₂-Ph), 2.80 (d-d, 1H CH₂Ph),3.12, (m, 1H, NCH), 3.36 (d-d, 1H, CH₂O), 3.64 (d-d, 1H, CH₂O),7.18-7.34 (m, 5H, PhH). ¹³C NMR: 8138.95, 129.47, 128.85, 126.69, 66.64,54.43, 41.22.

Results and Discussion

The phase appearances of various L/A combinations at room temperatureand −20° C. before and after bubbling CO₂ are shown in FIG. 20.Significantly, unlike amino ester/amidine system, all the combinationsformed clear, nearly colorless ionic liquids after exposure to CO₂ atroom temperature, although some of the original mixtures were not fluentliquids. Similarly, all the L-A-C remained liquids even at −20° C. It islikely that the types of cations and anions do not significantly affectthe phase appearances in this L/A system. As expected, the L/A mixturesare less viscous than the corresponding L-A-C ionic liquids.Qualitatively, the viscosity of some ionic liquids obtained from PheOHand NorOH, the phenyl-substituted amino alcohols, are higher than thoseobtained from alkyl-substituted amino alcohols. The presence of hydrogenbonding and other ion interactions might give rise to the high viscosityof ionic liquids (but still maintained their fluidity). In general, theresulting L-A-C ionic liquids are stable at room temperature and oneatmosphere of pressure, and the maximum temperature at which L-A-Cstarts to lose CO₂ is ca. 50° C. according to TGA measurements.

The amino alcohol L/A systems appear to tolerate a certain amount (10%)of water in either the neutral or polar state, although the reactionswere performed in dry condition. Also, the addition of water to a L/Amixture did not impede the formation of L-A-C upon bubbling CO₂ and noprecipitate or cloudy appearance was observed.

The formation of amidinium carbamates was confirmed by severalmeasurements, such as % CO₂ uptake, FT-IR, TGA, ¹H and ¹³C NMR. Theabsorption of CO₂ by our amino alcohol/amidine systems wasquantitatively measured by using a gas burette containing 1 atm pressureof dry CO₂ at room temperature. Analysis of Leucinol/C8 and Valinol/C8showed the rate of CO₂ uptaken by these mixtures was fast in first 10min, and reached the theoretical value 100% at approximately 30 min. Thefairly slow absorption of CO₂ was observed after 30 min and 10% excessCO₂ was uptaken until reaching a plateau after 60 min. The end-pointvalues around 110% indicate both chemically fixed and physicallydissolved carbon dioxide. The initial rapid (ca. 100%) absorptioncorresponds to the complete conversion to RTILs, with excess (ca. 10%)CO₂ slowly dissolving into the RTIL phase afterward.

One of the remarkable advantages of amino alcohol L-A-C system is therapid and quantitative reversibility between nonionic and ionic liquidstates. In general, L-A-C ionic liquids could be returned to their nonionic precursor states by simply bubbling N₂ or argon at roomtemperature. Heating the ionic liquids at ca. 50° C. during exposure toN₂ or argon increased the speed of the reversal process.

Additional evidence of reversibility was obtained from conductivitymeasurements. Because viscosity can influence conductivity, themeasurements were conducted in CHCl₃ solution. The neutral IleOH/C8mixture had low conductivity. After bubbling CO₂ into the IleOH/C8 CHCl₃solution, the conductivity increased rapidly, indicating the formationof the IleOH—C8-C ionic liquid, and reaching a plateau value of 268μs/cm. When N₂ was passed through the solution, the conductivitydecreased to 25 μs/cm, consistent with return to the neutral state fromthe L-C-A ionic liquid.

Ionic liquids are viewed as green alternatives to common volatileorganic solvents. Therefore, assessment of their miscibility with othermolecular solvents is important, particularly for developing ILs forliquid-liquid extraction processes. The amino alcohol L-A-Cs aremiscible with highly polar solvents, such as water, DMSO and ethanol.With low polarity solvents, such as hexane, toluene and diethyl ether,two separate phases were observed, confirming that the L-A-Cs areimmiscible with these solvents. The L-A-C ionic liquids prepared fromphenyl-substituted amino alcohols (N or OH, PheOH), are immiscible oronly partly miscible with dichloromethane and ethyl acetate, whileC6-NorOH—C is also only partly miscible with chloroform. The other aminoalcohol L-A-Cs appeared to have good miscibility with dichloromethane,ethyl acetate and chloroform.

INCORPORATION BY REFERENCE

All of the U.S. patents and U.S. published patent applications citedherein are hereby incorporated by reference.

EQUIVALENTS

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, many equivalents to the specificembodiments of the invention described herein. It is, therefore, to beunderstood that the foregoing embodiments are presented by way ofexample only and that, within the scope of the appended claims andequivalents thereto, the invention may be practiced otherwise than asspecifically described and claimed.

1. A salt represented by:

wherein R₁ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂,—SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈,—SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈,—C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; R₂ represents H,halogen, alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl, alkenyl,cycloalkenyl, heterocycloalkenyl, alkynyl, aryl, heteroaryl, aralkyl,heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,—NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈,—S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈,—CH(R₈)₂, or —C(R₈)₃; R₃ represents H, halogen, alkyl, fluoroalkyl,cycloalkyl, heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈,—N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂,—C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈,—C(═NR₈)R₈, —C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; R₄represents H, halogen, alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl,alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl, aryl, heteroaryl,aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈,—OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,—S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈, —C(R₈)═C(R₈)₂,—C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; R₅ represents H, halogen, alkyl,fluoroalkyl, cycloalkyl, heterocycloalkyl, alkenyl, cycloalkenyl,heterocycloalkenyl, alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,—(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈,—C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈,—C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or—C(R₈)₃; R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂,—SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈,—SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈,—C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂)_(n)—NH₂; Yrepresents independently for each occurrence O or S; R₈ representsindependently for each occurrence —(CH₂)_(n)—CH₃, cycloalkyl, aryl, orheteroaryl; and n represents independently for each occurrence aninteger in the range 1-10 inclusive.
 2. The salt of claim 1, wherein R₁represents H, halogen, alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl,alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl, aryl, heteroaryl,aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂,or —C(R₈)₃; R₂ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂,—C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; R₃ represents H, halogen, alkyl,fluoroalkyl, cycloalkyl, heterocycloalkyl, alkenyl, cycloalkenyl,heterocycloalkenyl, alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,—(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; R₄represents H, halogen, alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl,alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl, aryl, heteroaryl,aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂,or —C(R₈)₃; R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂,—C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; and R₆ represents H, halogen, alkyl,fluoroalkyl, cycloalkyl, heterocycloalkyl, alkenyl, cycloalkenyl,heterocycloalkenyl, alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,—(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃.
 3. The saltof claim 1, wherein R₁ represents H, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; R₂ represents H,alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl, —(CH₂)_(n)—R₈,—CH(R₈)₂, or —C(R₈)₃; R₃ represents H, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; R₄ represents H,alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl, —(CH₂)_(n)—R₈,—CH(R₈)₂, or —C(R₈)₃; R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and R₆ representsH, alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl, —(CH₂)_(n)—R₈,—CH(R₈)₂, or —C(R₈)₃.
 4. The salt of claim 1, wherein R₁ represents H,alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl, —(CH₂)_(n)—R₈,—CH(R₈)₂, or —C(R₈)₃; R₂ represents H, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; R₃ represents H,alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl, —(CH₂)_(n)—R₈,—CH(R₈)₂, or —C(R₈)₃; R₄ represents H, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; R₅ represents H,alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl, —(CH₂)_(n)—R₈,—CH(R₈)₂, or —C(R₈)₃; R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and Y is O. 5.The salt of claim 1, wherein Y is O.
 6. The salt of claim 1, wherein Yis O; and R₁, R₃, and R₄ are methyl.
 7. The salt of claim 1, wherein Yis O; R₁, R₃, and R₄ are methyl; and R₂ represents n-C₄H₉, n-C₅H₁₁,n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇.
 8. (canceled)
 9. The salt of claim 1,wherein Y is O; R₁, R₃, and R₄ are methyl; R₂ represents n-C₄H₉,n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇; and R₅ is H.
 10. The salt ofclaim 1, wherein R₁, R₃, and R₄ are methyl; R₂ represents n-C₄H₉,n-C₅H₁₁, n-C₆H₁₃, n-C₇H₁₅, or n-C₈H₁₇; Y is O; R₅ is H; and R₆represents n-C₄H₉, sec-C₄H₉, t-C₄H₉, cyclohexyl, n-C₆H₁₃, n-C₈H₁₇,—C₂H₄NH₂, or —C₆H₁₂NH₂.
 11. The salt of claim 1, wherein R₁, R₃, and R₄are methyl; R₂ is n-C₈H₁₇; Y is O; R₅ is H; and R₆ represents n-C₄H₉ orn-C₈H₁₇. 12-26. (canceled)
 27. A salt represented by:

wherein R₉ is absent or represents one or more substituents attached tothe ring, each of which is independently selected from the groupconsisting of H, halogen, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂,—SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈,—SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈,—C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, and —(CH₂)_(n)—NH₂;z is zero or an integer in the range of 1 to 3; R₅ represents H,halogen, alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl, alkenyl,cycloalkenyl, heterocycloalkenyl, alkynyl, aryl, heteroaryl, aralkyl,heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,—NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈,—S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈,—CH(R₈)₂, or —C(R₈)₃; R₆ represents H, halogen, alkyl, fluoroalkyl,cycloalkyl, heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈,—N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂,—C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈,—C(═NR₈)R₈, —C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or—(CH₂)_(n)—NH₂; Y represents independently for each occurrence O or S;R₈ represents independently for each occurrence —(CH₂)_(n)—CH₃,cycloalkyl, aryl, or heteroaryl; and n represents independently for eachoccurrence an integer in the range 1-10 inclusive.
 28. The salt of claim27, wherein R₉ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂,—C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; R₅ represents H, halogen, alkyl,fluoroalkyl, cycloalkyl, heterocycloalkyl, alkenyl, cycloalkenyl,heterocycloalkenyl, alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,—(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; and R₆represents H, halogen, alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl,alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl, aryl, heteroaryl,aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂,or —C(R₈)₃.
 29. The salt of claim 27, wherein R₉ represents H, alkyl,fluoroalkyl, cycloalkyl, heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or—C(R₈)₃; R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and R₆ representsH, alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl, —(CH₂)_(n)—R₈,—CH(R₈)₂, or —C(R₈)₃.
 30. The salt of claim 27, wherein R₉ represents H,alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl, —(CH₂)_(n)—R₈,—CH(R₈)₂, or —C(R₈)₃; R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; R₆ represents H,alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl, —(CH₂)_(n)—R₈,—CH(R₈)₂, or —C(R₈)₃; and Y is O. 31-50. (canceled)
 51. A saltrepresented by:

wherein R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂,—SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈,—SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈,—C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂)_(n)—NH₂;R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂,—SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈,—SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈,—C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃, or—(CH₂)_(n)—NH₂; Y represents independently for each occurrence O or S;R₈ represents independently for each occurrence —(CH₂)_(n)—CH₃,cycloalkyl, aryl, or heteroaryl; and n represents independently for eachoccurrence an integer in the range 1-10 inclusive.
 52. The salt of claim51, wherein R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂,—C≡CR₈, —CH(R₈)₂, or —C (R₈)₃; and R₆ represents H, halogen, alkyl,fluoroalkyl, cycloalkyl, heterocycloalkyl, alkenyl, cycloalkenyl,heterocycloalkenyl, alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,—(CH₂)_(n)—R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃.
 53. The saltof claim 51, wherein R₅ represents H, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and R₆ representsH, alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl, —(CH₂)_(n)—R₈,—CH(R₈)₂, or —C(R₈)₃.
 54. The salt of claim 51, wherein R₅ represents H,alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl, —(CH₂)_(n)—R₈,—CH(R₈)₂, or —C(R₈)₃; R₆ represents H, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, —(CH₂)_(n)—R₈, —CH(R₈)₂, or —C(R₈)₃; and Y is O.55-63. (canceled)
 64. A method of preparing a salt, comprising the stepof contacting a gas with a first compound and a second compound, whereinsaid first compound is selected from the group consisting of

wherein R₁ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂,—SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈,—SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈,—C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; R₂ represents H,halogen, alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl, alkenyl,cycloalkenyl, heterocycloalkenyl, alkynyl, aryl, heteroaryl, aralkyl,heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,—NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈,—S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈,—CH(R₈)₂, or —C(R₈)₃; R₃ represents H, halogen, alkyl, fluoroalkyl,cycloalkyl, heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈,—N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂,—C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈,—C(═NR₈)R₈, —C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; R₄represents H, halogen, alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl,alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl, aryl, heteroaryl,aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈,—OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,—S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈, —C(R₈)═C(R₈)₂,—C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; R₈ represents independently for eachoccurrence —(CH₂)_(n)—CH₃, cycloalkyl, aryl, or heteroaryl; and nrepresents independently for each occurrence an integer in the range1-10 inclusive; R₉ is absent or represents one or more substituentsattached to the ring, each of which is independently selected from thegroup consisting of H, halogen, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂,—SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈,—SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈,—C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, and —(CH₂)_(n)—NH₂;z is zero or an integer in the range of 1 to 3; and said second compoundis represented by

wherein R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂,—SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈,—SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈,—C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂)_(n)—NH₂;R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂,—SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈,—SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈,—C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, —(CH₂)_(n)—NH₂; R₈represents independently for each occurrence —(CH₂)_(n)—CH₃, cycloalkyl,aryl, or heteroaryl; n represents independently for each occurrence aninteger in the range 1-10 inclusive; and said gas is represented by:Y═X═Y wherein X represents C or N; and Y represents independently foreach occurrence O or S. 65-101. (canceled)
 102. A method comprising thestep of contacting a first gas with an ionic liquid, thereby generatinga second gas; wherein said ionic liquid is represented by:

wherein said first gas is an inert gas; said second gas is CO₂ or CS₂;R₁ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂,—SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈,—SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈,—C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; R₂ represents H,halogen, alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl, alkenyl,cycloalkenyl, heterocycloalkenyl, alkynyl, aryl, heteroaryl, aralkyl,heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,—NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈,—S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈,—CH(R₈)₂, or —C(R₈)₃; R₃ represents H, halogen, alkyl, fluoroalkyl,cycloalkyl, heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈,—N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂,—C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈,—C(═NR₈)R₈, —C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; R₄represents H, halogen, alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl,alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl, aryl, heteroaryl,aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈,—OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,—S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈, —C(R₈)═C(R₈)₂,—C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; R₅ represents H, halogen, alkyl,fluoroalkyl, cycloalkyl, heterocycloalkyl, alkenyl, cycloalkenyl,heterocycloalkenyl, alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,—(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈,—C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈,—C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂,—C(R₈)₃, or —(CH₂)_(n)—NH₂; R₆ represents H, halogen, alkyl,fluoroalkyl, cycloalkyl, heterocycloalkyl, alkenyl, cycloalkenyl,heterocycloalkenyl, alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,—(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈,—C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈,—C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂,—C(R₈)₃, or —(CH₂)_(n)—NH₂; Y represents independently for eachoccurrence O or S; R₈ represents independently for each occurrence—(CH₂)_(n)—CH₃, cycloalkyl, aryl, or heteroaryl; R₉ is absent orrepresents one or more substituents attached to the ring, each of whichis independently selected from the group consisting of H, halogen,alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl, alkenyl, cycloalkenyl,heterocycloalkenyl, alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,—(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈,—C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈,—C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂,—C(R₈)₃, and —(CH₂)_(n)—NH₂; z is zero or an integer in the range of 1to 3; and n represents independently for each occurrence an integer inthe range 1-10 inclusive. 103-151. (canceled)
 152. A method of removinga gas from a mixture, comprising the step of contacting said mixturewith a first compound and a second compound, wherein said first compoundis selected from the group consisting of

wherein R₁ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂,—SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈,—SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈,—C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; R₂ represents H,halogen, alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl, alkenyl,cycloalkenyl, heterocycloalkenyl, alkynyl, aryl, heteroaryl, aralkyl,heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈,—NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈,—S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈,—CH(R₈)₂, or —C(R₈)₃; R₃ represents H, halogen, alkyl, fluoroalkyl,cycloalkyl, heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl,alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈,—N(R₈)₂, —SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂,—C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈,—C(═NR₈)R₈, —C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; R₄represents H, halogen, alkyl, fluoroalkyl, cycloalkyl, heterocycloalkyl,alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl, aryl, heteroaryl,aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂, —SR₈, —C(═O)OR₈,—OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈, —SC(═O)R₈, —S(═O)R₈,—S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈, —C(═S)R₈, —C(R₈)═C(R₈)₂,—C≡CR₈, —CH(R₈)₂, or —C(R₈)₃; R₈ represents independently for eachoccurrence —(CH₂)_(n)—CH₃, cycloalkyl, aryl, or heteroaryl; and nrepresents independently for each occurrence an integer in the range1-10 inclusive; R₉ is absent or represents one or more substituentsattached to the ring, each of which is independently selected from thegroup consisting of H, halogen, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂,—SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈,—SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈,—C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂)_(n)—NH₂; zis zero or an integer in the range of 1 to 3; and said second compoundis represented by

wherein R₅ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂,—SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈,—SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈,—C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂)_(n)—NH₂;R₆ represents H, halogen, alkyl, fluoroalkyl, cycloalkyl,heterocycloalkyl, alkenyl, cycloalkenyl, heterocycloalkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, —(CH₂)_(n)—R₈, —OR₈, —N(R₈)₂,—SR₈, —C(═O)OR₈, —OC(═O)R₈, —NR₈C(═O)R₈, —C(═O)N(R₈)₂, —C(═O)SR₈,—SC(═O)R₈, —S(═O)R₈, —S(═O)₂R₈, —S(═O)₂OR₈, —C(═O)R₈, —C(═NR₈)R₈,—C(═S)R₈, —C(R₈)═C(R₈)₂, —C≡CR₈, —CH(R₈)₂, —C(R₈)₃, or —(CH₂)_(n)—NH₂;R₈ represents independently for each occurrence cycloalkyl, aryl, orheteroaryl; n represents independently for each occurrence an integer inthe range 1-10 inclusive; and said gas is represented by:Y═X═Y wherein X represents C or N; and Y represents independently foreach occurrence O or S. 153-189. (canceled)